I’m about to go on a trip with a troop of Boy Scouts, and the question came up as to whether a minor can sign and use traveler’s cheques. Anyone out there know the rules?
Well, I started using them when I was 12. They were the American Express type.
Unless the rules have changed you should be just fine. 
Minors can use them, but lots of places won’t accept them from minors. Businesses are not required to conduct business with minors as minors cannot legally enter into a contract (a sale is considered an oral contract).
Best check into pre-paid ATM cards or a credit card in your child’s name (which is guaranteed by the parents, of course).